posix/src/signal_2.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup POSIXAPI
0007  *
0008  * @brief POSIX Function Installs signal Handler
0009  */
0010
0011 /*
0012  *  signal(2) - Install signal handler
0013  *
0014  *  COPYRIGHT (c) 1989-1999.
0015  *  On-Line Applications Research Corporation (OAR).
0016  *
0017  * Redistribution and use in source and binary forms, with or without
0018  * modification, are permitted provided that the following conditions
0019  * are met:
0020  * 1. Redistributions of source code must retain the above copyright
0021  *    notice, this list of conditions and the following disclaimer.
0022  * 2. Redistributions in binary form must reproduce the above copyright
0023  *    notice, this list of conditions and the following disclaimer in the
0024  *    documentation and/or other materials provided with the distribution.
0025  *
0026  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0027  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0028  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0029  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0030  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0031  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0032  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0033  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0034  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0035  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0036  * POSSIBILITY OF SUCH DAMAGE.
0037  */
0038
0039 #ifdef HAVE_CONFIG_H
0040 #include "config.h"
0041 #endif
0042
0043 #include <signal.h>
0044 #include <errno.h>
0045
0046 #ifndef HAVE_SIGHANDLER_T
0047   typedef void (*sighandler_t)(int);
0048 #endif
0049
0050 sighandler_t signal(
0051   int           signum,
0052   sighandler_t  handler
0053 )
0054 {
0055   struct sigaction s;
0056   struct sigaction old;
0057
0058   s.sa_handler = handler ;
0059   sigemptyset(&s.sa_mask);
0060
0061   /*
0062    *  Depending on which system we want to behave like, one of
0063    *  the following versions should be chosen.
0064    */
0065
0066 /* #define signal_like_linux */
0067
0068 #if defined(signal_like_linux)
0069   s.sa_flags   = SA_RESTART | SA_INTERRUPT | SA_NOMASK;
0070   s.sa_restorer= NULL ;
0071 #elif defined(signal_like_SVR4)
0072   s.sa_flags   = SA_RESTART;
0073 #else
0074   s.sa_flags   = 0;
0075 #endif
0076
0077   sigaction( signum, &s, &old );
0078   return (sighandler_t) old.sa_handler;
0079 }